Manufacture of crockery washtubs



'No Model.) 3 SheetsS heet 1. W. D. STEWART. MANUFACTURE OF OROGKERY WASHTUBS.

No. 560,049. Patented May 12, 1896.

Mfg $12M)? (No Model.) 3 Sheets-Sheet 2.

W. D. STEWART.

MANUFACTURE OF GROGKERY WASHTUBS.

N0.560,049. I entedMay12,I896.

i! x 1'1 n 1 ll E .B

ANDREW B GRAHAM, MOTULRKOYWASHINEIONJ c.

(No Model.) 3 Sheets-Sheet 3.

W. D. STEWART.

1 I MANUFACTURE OF UROCKBRY WASHTUBS.

Patented May 12, 1 896.

NITED STATES PATENT OFFICE.

lVlLLlAM D. STEXVART, OF BROOKLYN, NEYV YORK.

MANUFACTURE OF CROCKERY WASHTU BS.

SPECIFICATION forming part of Letters Patent No. 560,049, dated May 12, 1896.

Application filed June 9,189 Serial No. 514,033. (No model.)

To all whom it ntay concern.-

Be it known that I, WILLIAM D. STEWART, a citizen of the United States, residing in the city of Brooklyn, Kings county, in the State of New York, have invented a certain new and useful Improvement in the Manufacture of Crockery \Vashtubs, of which the following is a specification.

A large crockery article, like a washtub, is liable to be subject to great initial strains due to various causes, one of which is inequality in shrinking in the burning. In many cases the strain induces cracks which ruin the article, and in all it is objectionable by weakening the structure and rendering it less liable to withstand strains to which it may be subjected in the setting or concussions from blows. The ordinary method of manufacturin g crockery washtubs by producing the clay in separate piecesfive plane sections forming, respectively, the front and back sides, the two ends and the bottom, and joining the edges by subsequent operationsis almost certain to leave the joints, the lines of the angles, and parts immediately adjoining in a different condition from the other parts. I have discovered a means of manufacture which molds the whole in an inverted position in one homogeneous mass of nearly uniform consistency throughout. The liability of the whole structure to differ slightly and gradually from the bottom to the top, what is to be the upper edge being wetter and softer than the other parts, is largely corrected by the more rapid drying of that portion, the tub being held right side up during the long exposure to a circulation of air which necessarily precedes the burning. Even if there is a difference in the structure of the upper portion of the tub the transition is gradual, and the form of the article allows a correspondingly increased or diminished shrinkage of the upper part without inducing cracks or severe strains. I have devised mechanism for molding tubs in this manner, each in a single complete article, proceeding rapidly and producing with proper care in the preparation of the clay and in the several manipulations practically uniform tubs, which are subject to little or no initial strain.

The accompanying drawings form a part of this specification and represent what 1 consider the best means of carrying out the invention.

Figure l is a central vertical section, partly in elevation. Fig. 2 is a corresponding section in a plane at right angles to that in Fig. 1. Figs. 3 to 7, inclusive, are details detached. Fig. 3 is a perspective view of a flat rectangular frame which lies under the base of the inverted tub during the process of molding. Fig. at shows in perspective the devices for separating the nearly-completed tub from the remaining material. Fig. 5 is a cross-section through these parts on a larger scale. Fig. 6 is a plan view of a portion seen from below. Fig. 7 is a perspective view of the core which is used to lead the stifliy-wrought clay out from the central portion and cause it to be depressed forcibly into the narrow spaces which mold the sides and ends of the tub. Fig. Sis an elevation of the internal mold with a section of the flexible covering which envelops it, the thickness of the latter being exaggerated. Fig. 9 is a vertical section through a portion on a larger scale. Fig. 10 is a side view on the same scale, showing the end of one of the horizontal sliding rods or plugs.

Similar letters of reference indicate corresponding parts in all the figures where they appear.

A is a vertically-mounted rectangular casing of cast-iron or other suitable material, and B a corresponding plunger fitting therein and stoutly connected by the rod B to a properlypacked piston B in a stout cylinder O, having a connection 0 to one or more pumps D, with means for operating them, constituting a powerful hydraulic press. The lower face of the plunger B is oblique or beveled, as indicated, and a soft removable packing E of hemp or other suitable material fitted in a slight rabbet around the lower edge makes this plunger practically tight in acting on a mass of uniformly and stifily tempered clay below. The parts must be capable of exerting a strong pressure on the clay. The lower edge of the casing A is inclined at an angle of about twenty-five degrees and presents at a certain stage a smooth and continuous surface, across which fine wire may be drawn by a sufficient force to separate the tub molded below from the clay remaining above.

F is a stout deflecting-piece, which I term a core, supported in the lower portion of the casing A and having its upper faces inclined to aid in deflecting the clay toward the walls of the casing. This core may be taken out and the inclination of its faces changed, as found necessary, to modify the proportions in which the clay isforced in different directions, the object being to make the front and back side and the ends of the tub as uniform as possible.

G is a casing of cast-iron or other suitable material, having the form of the exterior of the tub to be molded, but sufficiently larger to allow for a liberal thickness of wood H, which is a removable lining made in four seciions, one section lying on and molding the inclined front of the tub,another section molding the nearly perpendicular back of the tub, and the other sections molding the two ends of the tub. The mold is covered with muslin, which latter applies against the clay, its action being modified by the wood which backs it. The yielding quality of wood and its facility for gradually absorbing and giving out water renders it peculiarly adapted for this purpose.

It will be observed that my apparatus molds the tub in an inclined position. The part which molds the interior of the tub may be raised and lowered in a correspondingly-inclined position; but I have not experimented sufficiently to determine whether such is necessary or desirable. I will represent it as arranged to be moved vertically.

I is a strong platform inclined to correspond to the inclination of the base of the casing J. Suitable means, as wheels, (not shown,) may be provided to facilitate the movement of this platform and the connected parts horizontally in taking away a tub which has been molded and returning the same or another similar part in the unloaded condition to be used in holding the next tub. This is equipped with stout projections, which connect it detachably by the hooks K to the casing G. On this inclined removable platform I is mounted a stout plate IV, having'holes w, on which is placed a hollow mold, which is a framing of iron J, covered with wood J the latter being faced on its exterior with muslin. The form of this mold, and especially of the interior of the wood J, is carefully adapted to that of the inclosing parts H to provide that the tub produced inthe just suflicient space between shall be of the proper thickness, either uniform throughout or growing somewhat less toward what is to be the upper edge, as shall be found most expedient in practice. The upper edge of the outer mold G H is inclined to an extent corresponding to that of the inclined bottom of the casing A and is held close to it. The shell G of the outer mold is very firmly and tightly connected to the casingA by stout flanges, the faces of which are held apart near their inner edges to allow room for the wire. The parts are so adjusted that when a wire is drawn across in the joint between these parts it will cut ofi and leave on the mold a just sufficient thick ness of homogeneous clay to produce the bot tom of the tub.

The core F is held up strongly by securing it to a cross-piece F by a bolt F set through a large hole, so as to allow of slight changes of position. This combination also gives facility for disconnecting therefrom by a complete removal of the bolt to allow of changing the form of the core or substituting a different one. The changes in the form and position should be made after trial until the several faces of the tub shall be molded with uniform hardness. I provide for moving inward a portion of the innermold which shapes the corrugations. It is common to employ corrugations covering a considerable area of the interior of the inclined side of the tub. My mold is equipped to produce such. The portion which effects the molding of this part is drawn inward toward the center of the inner mold before the latter is detached.

J 2 is a rectangular plank covering the area on which it is desired to produce the corrugations, fitting loosely in a corresponding rectangular aperture in the wood covering J on that face. It is provided on its outer face with horizontal ridges and grooves, which it is desired to reproduce in the tub, these features being sufficiently sharp to give the corresponding surface of the finished tub the required corrugations, notwithstanding the softening effect due to the muslin jacket P. The inner face of this movable portion J 2 is provided with arms J which are received in guides J the arrangement allowing the plank J and its attachments to move bodily outward and inward to the required extent.

R is an upright shaft supported in bearings near the center of the lower mold J and having a short lever or crank at its upper end, which connects by a link S with the inner face of the plank J In adjusting the device for work the squared lower end of the shaft R is taken hold of by a suitable lever or wrench and the shaft R turned half around, throwing the cranked end toward the plank J This by the action of the link S moves the plank outward to make the ridges thereon sufliciently prominent. After the molding is complete and it is required to remove the inner mold the wrench is again applied and the shaft R turned another half-revolution. This turns the crank in the opposite direction and, through the action of the link S, draws the plank J 2 inward sufficiently to disengage its corrugations from the clay which has been molded thereby. Now the inner mold is free to be depressed without difficulty, leaving the inclined face with the properly-molded ridges thereon. It will be understood that the surface of the bottom and all the other parts may be, and ordinarily will be, slickened by hand or machinery with the aid of proper tools after the molding is complete. A series of LII small holes win the plate Wand corresponding holes 1' are formed in the platform I in position to drain the lower edge of the mold. The strong pressure to which the clay is subjected by the depression of the plunger B causes the clay to move downward, being directed outward to the periphery by the core F, and it commences to flow down in what is to mold the sides and ends of the tub; but in this operation the water goes more freely than the dense clay, and it will follow that the first clay arriving at the bottom of the mold-the portion which molds what is ultimately the upper edge or rim of the tub-will be thinner than the proper consistency. This thin clay exudes through the holes 1', and when all are delivering each its small rope of clay the attendant knows that the molding is nearlycompleted; but he allows it to proceed until the clay thus exuding has attained a sutlicient consistency. Then the operation is considered complete. The core is at such height that there is ample space under it for the clay to flow inward of the proper consistency to mold what is to be the bottom of the tub. Next the action of the hydraulic press which drives the plunger B downward is arrested and its pressure is relaxed and the plunger is slightly lifted to relieve the clay from pressure during the succeeding steps.

The joint or thin space which is required between the parts to allow the passage of the wire would allow the escape of the clay in a thin sheet in all directions and prevent the success of the operation unless some means were provided for stopping it until the molding is complete. I form the base of the casing A and the upper edge of the mold G each with a sufficiently thick flange, as shown in Figs. 1, 2, and 9, and produce by milling or by other suitable means grooves a of semicylindrical cross-section, extending along in the plane of the bottom of the tub and lying partly in the flange at the base of the casing A and partly in the flange of the mold G. By making the groove in the upper part a little larger than that in the lower part and planing off or otherwise removing the metal of the part A which lies interior to the grooves I allow a proper space for the wire to move freely. In the grooves I lit plugs M of corresponding section. lVhen these are turned in the position shown in Fig. 9, they tightly close the joints and prevent the escape of the clay. This condition obtains while the plunger is being depressed and the clay is being forced down into the mold. lVhen this operation, which may occupy from two to five minutes, is completed, which fact will be indicated by the escape of dense clay through the holes 1', and it is required to operate the wire, the hydraulic press 0 is relieved from pressure and each plug M is partially revolved on its axis, so that it is loosened, and both are drawn outward either steadily or intermittently. A fine steel wire m, connecting the ends of these latter plugs, is by this movement carried across the base of the tub being formed, and when the plugs have been completely drawn out the wire 'm has completely separated the clay. The clay which tends to escape in a thin sheet on the other two sides the ends may be arrested,if required,by a suitable covering-piece A,applied on the outside. These covering-pieces must be removed after the clay is forced down and before the wire is drawn across. IVhen the parts have attained this condition, the fastenings K are detached and the inner mold is ready to be lowered. This operation, being resisted by the strong adhesion of the clay to the adjacent surfaces, will ordinarily require some assistance. This may be effected by introducing suitable hand-tools, (not shown,) but which may be analogous in form and character to the tangs of stout files. These tools, being introduced through the holes g at the mid-height in the several faces, take hold of the wood linings II and allow them to be worked downward in the outer mold G. After the several parts of the lining II have been liberated by this operation the platform I and the internal mold J supported thereon may be lowered. In this movement the freshlymolded tub sinks with it and also the four fiat parts II of the outer mold. It will be understood that these several parts, the internal mold J, the freshly-molded tub, and the four lining-pieces H of the outer mold, all sink more or less rapidly until the parts are entirely clear of the outer mold G. Then they may be all moved laterally and the operation is so far completed. Next the several liningpieces H can be easily detached from the several faces of the freshly-molded tub and may, after the removal of any clay from the exterior, be again returned into the correspondingly clean interior of the outer mold G and held by any suitable means, as spring-clips. (Not shown.) Now the same or another similar platform I, plate IV, and internal mold J may be brought into position and raised and secured and the operation repeated. The plugs M are carefully returned to their places and turned into such position that they tightly stop the joint and prevent any escape of the clay before the pressure is again applied.

The exterior of the freshly-molded tub will ordinarily require more or less trimming by hand. This is easy. The edges of the tub are allowed to rest on the plate W and the internal mold J is depressed. The removal of the internal mold may in some cases require patience; but it is aided by the employment of a detachable jacket of stout muslin P, which has the proper form for the interior of the tub and will remain cohering to the clay and allow the mold to be depressed with tolerable freedom. After the parts have been thus separated it is easy to detach the flexible jacket P by commencing at any corner and proceeding gradually over the whole surface. After it has been removed it may be, with or without cleaning, returned again to place on the mold J, and the tub, being turned right side up and properly slickened, is ready to be set aside and subjected to the drying process.

Modifications may be made without departing from the principle or sacrificing the advantages of the invention.

Parts of the invention can be used without the whole. I can omit the core F and depend upon the inclination of the lower face of the plunger B to direct the clay to form the sides and ends of the tub with sufficient uniformity, or I can omit the beveling of the under side of the plunger and depend upon the core alone to give the required uniformity in the direction of the pressure.

Instead. of making the casing A upright and holding the joint at its base inclined, I can obviously set the casing inclined and have the joint level. I consider such mechanism equivalent each to the other, but esteem the arrangement shown to be preferable.

I claim as my invention- 1. The hollow casing A, having the inclined base, the plunger B, and means as a hydraulic press for operating it, in combination with the outer mold G, having a correspondinglyinclined upper face, the inner edges of which are held at a small distance from A and the outer portions stifily connected and with the wire m traversed across, all arranged to serve relatively to each other and to the clay, as herein specified.

2. The hollow casing A, having an inclined base, a plunger 13, and means as a hydraulic press for operating it, in combination with the outer mold G having a correspondinglyinclined upper face held at a small distance from A, the parts being stiffiy connected, and the wire on traversed across the wood faces H detachably inclosed within the casing G, all arranged for joint operation substantially as herein specified.

3. The hollow casin g A, having an inclined base, a plunger B and means as a hydraulic press for operating it, in combination with an outer mold G having a correspondingly-inclined upper face held at a small distance from the casing A, and the bottom J having a series of holes 71 near the edges, adapted to allow the earliest and thinnest clay which de scends to exude, all substantially as herein specified.

l. The hollow casin g A, having an inclined base, plunger B, and means as a hydraulic press, for operating it, in combination with an outer mold G, having a correspondingly-inclined upper face held at a small distance from the casing A, and having holes g adapted to allow the wood faces to be loosened by operating therethrough, and with the wire on traversed across, all substantially as herein specified.

5. The hollow casing A, having an inclined base, a plunger B and means as a hydraulic press for operatin g it, in combination with an outer mold G having a correspondingly-inclined upper face held at a small distance from the casing A, and provisions as bolts for stiffly connecting these parts, and the wire on traversed across in the space thus provided, the interior mold J and the wood faces H detachably inclosed within the outer casing G, and with the movable portion J 2 andmeans for thrusting it outward to shape the corrugations, and for drawing it inward to facilitate the separation of the interior mold from the molded tub, all substantially as herein specified.

6. The hollow casing A, plunger B and means for operating it, outer mold G, II, having the form for shaping the exterior of the tub, and inner mold J, having the form for shaping the main portion of the interior of the tub, in combination with each other and with a deflecting-core F adapted to adjust the relative force with which the clay is depressed into the several parts of the mold, as herein specified.

7 The hollow casing A, plunger 13 and means for operating it, outer mold G, H, having the form for shaping the exterior of the tub, and inner mold J, having the form for shaping the main portion of the interior of the tub, in combination with each other and with provisions for holding the parts G and A firmly at the proper distance apart to allow the passage of the wire m, and with the plugs M adapted to open and close the space bet-ween these parts, all arranged for joint operation as herein specified.

8. The hollow casing A, plunger B, and means for operating it, outer casing G, H, having the form for shaping the exterior of the tub, and inner mold J, having the form for shaping the main portion of the interior of the tub, in combination with each other and with means for holding the parts G and A firmly at the proper distance apart to allow the passage of the wire m, and with the plugs M adapted to open and close the space be tween these parts, and with the wire at attached to these plugs so as to cut off the clay by the act of withdrawing the plugs, all substantially as herein specified.

In testimony that I claim the invention above set forth I affix my signature in presence of two witnesses.

VILLIAM D. STEIVART.

'itnesses:

II. A. SrETsoN, M. F. BOYLE.

IIO 

